Preparation of 1,4-butanediol

ABSTRACT

1,4-Butanediol is prepared by a process which comprises converting 1,3-butadiene diepoxide in the presence of hydrogen over a hydrogenation catalyst whose active component is not elemental Pd and/or Pt. The hydrogenation catalyst preferably contains at least one element from the group Ib, VIIb or VIIIb of the Periodic Table of Elements.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This is a Divisional Application of application Ser. No. 08/523,887,filed on Sep. 6, 1995, which stands allowed.

BACKGROUND OF THE INVENTION

The present invention relates to a process for the preparation of1,4-butanediol by hydrogenation of 1,3-butadiene diepoxide.

1,4-Butanediol is an important chemical component for syntheses and isproduced worldwide; it is used, for example, as a starting material forthe synthesis of epoxy resins, polyesters, polyamides and polyurethanes.Traditionally, it is prepared by hydrogenation of 2-butyne-1,4-diol,which in turn is the product of a Reppe synthesis from acetylene andformaldehyde.

The catalytic hydrogenolysis of oxiranes has been described in manypublications. An overview of the hydrogenolytic cleavage of oxiranes toalcohols over various hydrogenation catalysts is given, for example, inHouben-Weyl, Methoden der Organischen Chemie, Volume VI, 1a, Part 1,1979, pages 338 to 342. Palladium, platinum and nickel catalysts arementioned as conventional catalysts for the oxirane cleavage withhydrogenation.

Houben-Weyl, Methoden der Organischen Chemie, Volume VI, 3, 1965, pages442 to 446, describes the catalytic hydrogenation of asymmetric1,2-epoxides. As a rule for the regioselectivity of the cleavage of thethree-membered ring, it is stated that in general cleavage takes placebetween the oxygen atom and the carbon atom which carries the smallestnumber of hydrogen atoms.

The catalytic hydrogenation of oxiranes with cleavage of a C--O bond isalso described in Houben-Weyl, Methoden der Organischen Chemie, VolumeIV, 1c, 1980, pages 374 to 377. Here, it is stated that the literaturedata on the direction of the ring cleavage in asymmetrically substitutedoxiranes are in part contradictory. Nevertheless, in contradiction tothe literature reference stated in the preceding paragraph, the ruleformulated is that, where there is no activation by aryl or allyl groupsin asymmetrically substituted oxiranes, the C--O bond cleaved is thatwhich is least sterically shielded, ie. whose carbon atom carries thelargest number of hydrogen atoms.

The catalytic hydrogenation of 1,3-butadiene diepoxide is novel. Thecontradictory statements with regard to the selectivity in the ringcleavage in asymmetrically substituted oxiranes in the prior art do notpermit a prediction of the product to be expected, ie. 1,4-, 2,3- or1,3-butanediol.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a route to1,4-butanediol which avoids the Reppe synthesis and its unsafe catalystsand is nevertheless economical.

We have found that this object is achieved, according to the invention,by a process for the selective catalytic hydrogenation of 1,3-butadienediepoxide to 1,4-butanediol, which comprises converting 1,3-butadienediepoxide in the presence of hydrogen over a hydrogenation catalystwhose active component is not elemental palladium and/or platinum.

In the novel process, the surprisingly selective hydrogenolysis of theepoxide rings of 1,3-butadiene diepoxide takes place with formation of1,4-butanediol according to the following equation: ##STR1##

In carrying out the novel process, 1,3-butadiene diepoxide is convertedinto 1,4-butanediol in the presence of hydrogen and of a hydrogenationcatalyst as defined above, usually at from 1 to 300, preferably from 10to 250, in particular from 20 to 200, bar and at from 0 to 250° C.,preferably from 60 to 220° C., particularly preferably from 100 to 200°C.

The novel process can be carried out without a solvent or advantageouslyin the presence of a solvent which is inert under the reactionconditions. Such solvents may be, for example, ethers, such astetrahydrofuran, methyl tert-butyl ether or di-n-butyl ether, alcohols,such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol ortert-butanol, hydrocarbons, such as petroleum ether, and N-alkyllactams,such as N-methylpyrrolidone or N-octylpyrrolidone.

In the novel process, the hydrogenation catalysts may be present ingeneral in any form suitable for the hydrogenolysis of oxiranes. Thus,they may be hydrogenation catalysts which dissolve in the reactionmedium to give a homogeneous solution, as described, for example, inHouben-Weyl, Methoden der Organischen Chemie, Volume IV/1c, pages 45 to67.

In the novel process, however, heterogeneous hydrogenation catalysts arepreferably used, ie. hydrogenation catalysts which are essentiallyinsoluble in the reaction medium. Among these hydrogenation catalysts,preferred ones are those which contain one or more elements of thegroups Ib, VIIb and VIIIb of the Periodic Table of Elements, inparticular copper, rhenium, ruthenium, cobalt, rhodium, iridium, osmiumand/or nickel.

Heterogeneous hydrogenation catalysts which may be used in the novelprocess are those which consist of metals in active, finely divided formhaving a large surface area, for example Raney nickel, Raney cobalt orrhenium sponge.

For example, precipitated catalysts may also be used in the novelprocess. Such catalysts can be prepared by precipitating theircatalytically active components from their salt solutions, in particularfrom the solutions of their nitrates and/or acetates, for example byadding alkali metal and/or alkaline earth metal hydroxide and/orcarbonate solutions, as, for example, sparingly soluble hydroxides,hydrated oxides, basic salts or carbonates, then drying the precipitatesobtained and then converting them by calcination at in general from 300to 700° C., in particular from 400 to 600° C., into the relevant oxides,mixed oxides and/or mixed-valency oxides, which are reduced by treatmentwith hydrogen or with hydrogen-containing gases at in general from 100to 700° C., in particular from 150 to 400° C., to give the relevantmetals and/or oxidic compounds of low oxidation states and thusconverted into the actual, catalytically active form. As a rule,reduction is continued until water is no longer formed.

In the preparation of precipitated catalysts which contain a carrier,precipitation of the catalytically active components may be effected inthe presence of the relevant carrier. However, the catalytically activecomponents can advantageously also be precipitated simultaneously withthe carrier from the relevant salt solutions.

The activation of both the precipitated catalysts and the supportedcatalysts can also be carried out in situ in the reaction mixture by thehydrogen present there, but activation is preferably effected separatelybefore use.

The carriers used may be in general the oxides of aluminum and oftitanium, zirconium dioxide, silica, kieselguhr, silica gel, aluminas,eg. montmorillonites, silicates, such as magnesium silicates or aluminumsilicates, zeolites, such as ZSM-5 or ZBM-10 zeolites, or active carbon.Preferred carriers are aluminas, titanium dioxides, silicas, zirconiumdioxides and active carbon. Mixtures of different carriers may of coursealso be used as carriers for the catalysts which can be used in thenovel process.

The novel process can be carried out both continuously and batchwise. Inthe continuous procedure, it is possible to use, for example, tubereactors in which the catalyst is advantageously arranged in the form ofa fixed bed, over which the reaction mixture can be passed by the liquidphase or trickle-bed procedure. In the case of the batchwise procedure,both simple stirred reactors and, advantageously, loop reactors may beused. Where loop reactors are used, the catalyst is advantageouslyarranged in the form of a fixed bed. The novel process can be carriedout both in the gas phase and in the liquid phase.

The 1,3-butadiene diepoxide used as the starting material can beprepared, for example, by base-induced dehydrochlorination ofdichlorobutanediols according to Przem. Chem. 56 (1977) 5, 246-50, or bydehydrobromination of 1,4-dibromobutanediol according to SU 1057-502-A.In the absence of halogen, butadiene diepoxide can be prepared, forexample, by epoxidation of butadiene with hydrogen peroxide over atitanium silicalite as a catalyst, according to Chim. Ind. (Milan) 72(7), 610-16, or according to EP 100 119 A. Furthermore, butadienediepoxide can be prepared by epoxidation of butadiene with organic peracids according to JP 61072774 A or with cyclohexanone peroxide usingtitanium dioxide as a catalyst, according to EP 129 814. Finally,butadiene can be oxidized according to Zh. Obshch. Khim. 46 (6) (1976),1420, with atmospheric oxygen at 250° C. in a tube reactor to givebutadiene diepoxide.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Catalysts

In the unreduced state, the catalysts A to I used in the Examples havethe compositions stated in Table I (data in % by weight):

                  TABLE I                                                         ______________________________________                                        Catalyst                                                                              Preparation  Composition                                              ______________________________________                                        A       EP-A-100 406 67% CoO, 19% CuO, 7% Mn.sub.2 O.sub.3,                       3% MoO.sub.3, 3% H.sub.3 PO.sub.4, 0.2%                                       Na.sub.2 O                                                                  B EP-A-382 049 10% CoO, 10% NiO, 4% CuO,                                        76% Al.sub.2 O.sub.3                                                        C US-A-5,037,793 50% NiO, 17% CuO, 31% ZrO.sub.2,                               2% MoO.sub.3                                                                D 1) 1.5% Re, 3% Os, 1.5% K.sub.2 O,                                            94% C                                                                       E EP-A-44 444 56% CuO, 44% Al.sub.2 O.sub.3                                   F 2) 22.3% CuO, 77.7% SiO.sub.2                                               G 3) 2% Ru, 98% Al.sub.2 O.sub.3                                              H 4) 5% Pd, 95% C                                                             I 5) 1% Pt, 99% Al.sub.2 O.sub.3                                            ______________________________________                                         Footnotes:                                                                    1) 4 mm active carbon extrudates were impregnated with an aqueous Re(VII)     oxide solution, dried at 120° C. and treated with hydrogen at          250° C. The treated active carbon extrudates were then impregnated     with an aqueous K.sub.2 OsO.sub.4 hydrate solution, dried at 100°      C./20 mbar and activated with hydrogen at 250° C.                      2) 4 mm SiO.sub.2 extrudates were impregnated with an ammoniacal copper       carbonate solution, dried at 120° C., calcined at 350° C.       and then milled to chips.                                                     3) 1.5 mm SiO.sub.2 extrudates were impregnated with an aqueous ruthenium     hydrate solution, dried at 120° C. and calcined at 400° C.      4) 2 mm active carbon extrudates were impregnated with an aqueous             palladium nitrate solution and dried at 100° C.                        5) Source: Aldrich                                                       

EXAMPLE 1

In a 50 ml metal autoclave, 0.5 g of Raney cobalt was added to thesolution to be hydrogenated, comprising 2.5 g of rac-1,3-butadienediepoxide and 22.5 g of tetrahydrofuran, and hydrogenation was effectedwith hydrogen for 3 hours at 180° C. and 40 bar while stirring with amagnet stirrer. At a conversion of 98%, gas chromatographic analysisshowed that 80 mol % of 1,4-butanediol and 19 mol % of n-butanol hadbeen obtained.

EXAMPLE 2

The hydrogenation of 2.5 g of 1,3-butadiene diepoxide and 22.5 g oftetrahydrofuran was carried out as in Example 1, but over catalyst Ainstead of Raney cobalt. Catalyst A was first activated in a stream ofhydrogen for 2 hours at 250° C. and then used in the form of 4 mmextrudates. At quantitative conversion, 81 mol % of 1,4-butanediol, 16mol % of n-butanol and 3 mol % of 2,3-butanediol were found.

EXAMPLE 3

The hydrogenation of 2.5 g of 1,3-butadiene diepoxide and 22.5 g oftetrahydrofuran with 0.5 g of catalyst B was carried out as described inExample 1. Catalyst B was activated beforehand in a stream of hydrogenfor 1 hour at 250° C. and used in the form of 4 mm extrudates. At aconversion of 100%, 77 mol % of 1,4-butanediol and 8 mol % of n-butanolwere obtained.

EXAMPLE 4

The hydrogenation of 2.5 g of 1,3-butadiene diepoxide and 22.5 g oftetrahydrofuran with 0.5 g of Raney nickel was carried out at 140° C.and 40 bar in an apparatus as described in Example 1. After a reactiontime of 4 hours and at quantitative conversion, the reacted mixturecontained 74 mol % of 1,4-butanediol and 23 mol % of 2,3-butanediol.

EXAMPLES 5-9

The reaction conditions and the composition of the reacted mixture whichwere obtained in the hydrogenation of 2.5 g of 1,3-butadiene diepoxideand 22.5 g of tetrahydrofuran over, in each case, 0.5 g of the catalystsC-G at a total pressure of 40 bar are shown in Table II below.

Catalyst C was activated beforehand in a stream of hydrogen for 2 hoursat 200° C. and then used in the form of 3 mm pellets.

Catalyst D had been prepared beforehand by activation in a of hydrogenfor 1 hour at 150° C. and was used in the form of 4 mm extrudates.

Catalyst E was activated in a stream of hydrogen for 2 hours at 200° C.and then used in the form of 4 mm pellets.

Catalyst F was activated in the same way as catalyst E and then used inthe form of 2-4 mm chips.

Catalyst G was activated beforehand in a stream of hydrogen for 1 hourat 250° C. and used in the form of 1.5 mm extrudates.

    ______________________________________                                                      Reac.       Con-                                                  Ex-  time T version  [mol %]                                                  ample Catalyst [h] [° C.] [%] 1,4-BD 2,3-BD n-BuOH                   ______________________________________                                        5     C       1      180  97    64    16     8                                  6 D 4 180 88 57 -- 11                                                         7 E 4 140 98 53 -- 45                                                         8 F 4 140 99 30 -- 42                                                         9 G 4 180 97 31 -- 10                                                       ______________________________________                                    

1,4-butanediol, 1,2-BD: 2,3-butanediol, n-BuOH: n-butanol

COMPARATIVE EXAMPLE 1

The hydrogenation of 2.5 g of 1,3-butadiene diepoxide and 22.5 g oftetrahydrofuran was carried out with 0.5 g of catalyst H at 100° C. and40 bar in an apparatus as described in Example 1. The catalyst wasactivated beforehand in a stream of hydrogen for 1 hour at 120° C. andused in the form of 2 mm extrudates. After a reaction time of 4 hoursand at quantitative conversion, the reacted mixture contained 7 mol % of1,4-butanediol and 82 mol % of 2,3-butanediol.

COMPARATIVE EXAMPLE 2

The hydrogenation of 2.5 g of 1,3-butadiene diepoxide and 22.5 g oftetrahydrofuran was carried out with 0.5 g of catalyst I at 180° C. and40 bar in an apparatus as described in Example 1. The catalyst was usedin powder form without activation. After a reaction time of 4 hours andat a conversion of 73%, the reacted mixture contained 1 mol % of1,4-butanediol and 73 mol % of 2,3-butanediol.

We claim:
 1. A process for the preparation of 1,4-butanediol, whichcomprises converting 1,3-butadiene diepoxide in the presence of hydrogenover a hydrogenation catalyst which comprises Ni and which may furthercomprise one or more elements selected from the group consisting ofcobalt, copper, manganese, molybdenum, rhenium, osmium, ruthenium,rhodium and iridium.
 2. The process defined in claim 1, wherein thehydrogenation catalyst is a heterogeneous hydrogenation catalyst.
 3. Theprocess defined in claim 2, wherein the hydrogenation catalyst comprisesa carrier selected from the group consisting of oxides of aluminium andof titanium, zirconium dioxide, silica, kieselgur, silica gel, aluminas,silicates, zeolites and active carbon.
 4. The process defined in claim1, wherein the hydrogenation catalyst comprises a carrier selected fromthe group consisting of oxides of aluminium and of titanium, zirconiumdioxide, silica, kieselgur, silica gel, aluminas, silicates, zeolitesand active carbon.
 5. The process defined in claim 1, which is carriedout at from 0 to 300° C. and from 1 to 300 bar.
 6. The process definedin claim 1, which is carried out in a solvent.
 7. The process defined inclaim 1, wherein the hydrogenation catalyst contains cobalt.
 8. Theprocess defined in claim 1, wherein the hydrogenation catalyst containscopper.
 9. The process defined in claim 1, wherein the hydrogenationcatalyst contains rhenium.
 10. The process defined in claim 1, which iscarried out at from 60 to 220° C. and from 10 to 250 bar.